1. Field of the Invention
The present invention relates to a liquid atomizer, more particularly a kind of liquid atomizer capable of reducing noise, improving the service life of spray plate, preventing working frequency drift, and enhancing the atomization efficiency.
2. Description of the Related Art
Liquid atomizer currently available on the market comes in pressure type and mechanical oscillation type. The former atomizes liquid using pressure gradient and is able to atomize large amount of liquid. But pressure-type atomizer requires machine for pressurization, and generates greater noise. For medical atomizer, only small amount of liquid needs to be atomized, but the size of droplet produced is an important consideration. Thus the medical application of pressure-type atomizer gradually loses its appeal. Mechanical oscillation type atomizer has been the dominant type of medical atomizer in recent years that largely uses ultrasonic vibration generated by piezoelectric material to atomize liquid. But it also has the drawbacks of consuming too much power and requiring fans to direct the flow of droplet mist.
Aside from the ultrasonic atomization just described, there are piezoelectric atomizers that use spray plate to generate droplet mist. The use of spray plate greatly reduces the consumption of electric energy and better controls the droplet sizes through the working of pore size. Related patents or products of such atomizer can be generally categorized into two types: using the vibration of piezoelectric material to push the liquid through the spray holes to form mist, or using piezoelectric material to vibrate a spray plate causing it to push out the liquid, which turns into mist form after passing through the spray holes. The former requires greater energy to drive the piezoelectric material in order to atomize the liquid and generate smaller droplets, and is less efficient as compared to the latter. The latter contains spray plate, which is an active vibration component prone to fatigue. Other problems associated with the latter type of piezoelectric atomizers include noise during liquidless air vibration, reduced service life of spray plate in case of large-area vibration, working frequency drift following air vibration, and low atomization efficiency.
The liquid atomizer 60 in a typical atomizing device that uses active vibration component includes a vibrating element 70 and a spray plate 80. As shown in FIG. 6, the spray plate 80 vibrates under the driving of vibrating element 70 and generates squeeze pressure to push the liquid out of spray holes 81 and form droplet mist.
In the atomization process just described, the entire spray plate would vibrate under the driving of vibrating element for it is adhered to the vibrating element. Because of increase in its vibration area, the spray plate tends to fatigue easily, and increase in the spray plate load reduces the atomization efficiency.
As such, how to reduce the vibration area of the spray plate in the atomization process, enhance the service life of spray plate and improve the atomization efficiency, and prevent working frequency drift are problems that need to be addressed.